The radiating feeds operating in low frequency bands, for example in band C, generally comprise very bulky metal horns of significant weight. To reduce the size of the radiating feed, it is known practice, from the document FR2959611, to replace the metal horn with stacked Fabry-Pérot cavities. This solution makes it possible to reduce the size of the feeds and exhibits radio frequency performance levels equivalent to those of a metal horn. However, this solution is limited to an aperture diameter less than 2.5λ, where λ represents the central wavelength, in vacuum, of the frequency band of use.
In order to produce compact feeds of greater radiating aperture, the document FR 3012917 proposes a solution comprising a compact bipolarization power splitter comprising four asymmetrical orthomode transducers OMT, coupled in phase to a power source with dual orthogonal polarization. These four OMTs are networked together via two power distributers dedicated to each polarization. This power splitter has a very small thickness when the OMTs and the two power distributers are situated in one and the same plane. This solution does however present the drawback of a mediocre isolation, of the order of 15 dB, between the two orthogonal modes of each OMT, which results in inadequate performance levels for the power splitter. This isolation defect between the two orthogonal modes of each OMT is essentially due to the asymmetry of each OMT which comprises only two lateral access ports spaced apart angularly by 90° about a main waveguide.